THE CLEANING OR REMOVAL OF STAINS FROM STONE MAY INVOLVE THE USE
OF LIQUIDS, DETERGENTS OR SOLVENTS WHICH MAY RUN OFF ON ADJACENT
MATERIAL, DISCOLOR THE STONE OR DRIVE THE STAINS DEEPER INTO POROUS
STONES. USE THE PRODUCTS AND TECHNIQUES DESCRIBED HERE ONLY FOR
THE COMBINATIONS OF DIRT/STAIN AND STONE SPECIFIED.

PART 1---GENERAL

1.01 SUMMARY

A. This procedure includes guidance on the removal of
surface dirt and environmental pollution on exterior
limestone. GENERALLY, THIS WORK SHOULD BE ACCOMPLISHED
BY AN EXPERIENCED CONTRACTOR.

B. See 01100-07-S for general project guidelines to be
reviewed along with this procedure. These guidelines
cover the following sections:

1. Safety Precautions

2. Historic Structures Precautions

3. Submittals

4. Quality Assurance

5. Delivery, Storage and Handling

6. Project/Site Conditions

7. Sequencing and Scheduling

8. General Protection (Surface and Surrounding)

These guidelines should be reviewed prior to performing
this procedure and should be followed, when applicable,
along with recommendations from the Regional Historic
Preservation Officer (RHPO).

3. Prevent cleaning chemicals from coming in contact
with any painted, polished or metallic surfaces.

4. Divert flow of run-off to drains in compliance with
municipal codes. Comply with municipal codes
regarding containment and disposal of cleaning
materials.

B. Surface Preparation:

1. Before proceeding with cleaning operations, remove
all miscellaneous hardware, anchors and bird
excrement from the surface to prevent any
discoloration.

NOTE: BIRD EXCREMENT IN CONTACT WITH CLEANING
SOLUTION WILL LEAVE A PERMANENT DARK-COLORED STAIN
ON THE SURFACE.

2. Check for open holes and joints in surface and
repoint mortar joints and caulk gaps around window & door openings, as required to prevent water and
cleaning solutions from penetrating deeply into the
wall.

3. Clean the limestone working from bottom to top.

3.03 ERECTION, INSTALLATION, APPLICATION

NOTE: WHEN CLEANING, AVOID OVERCLEANING. AIM FOR ACHIEVING
85% CLEAN. MOST DAMAGE OCCURS WHEN ATTEMPTING TO CLEAN THE
LAST 15%.

NOTE: TEST CLEAN A SMALL AREA TO DETERMINE EFFECTIVENESS OF
CLEANING METHODS, MATERIALS, EQUIPMENT AND WORKING PRESSURES
SELECTED BEFORE PROCEEDING WITH CLEANING OPERATIONS ON LARGER
AREAS. ADJUST METHODS, MATERIALS, EQUIPMENT, PRESSURES, ETC.
AS NECESSARY. DO NOT PROCEED UNTIL AN ACCEPTABLE CLEANING
OPERATION HAS BEEN APPROVED AND FULLY DOCUMENTED.